A rock is dropped from a cliff and hits the ground 6.0 seconds later. How high is the cliff?

The height of the cliff can be calculated using the formula for free fall: h = (1/2)gt^2, where h is the height, g is the acceleration due to gravity (9.8 m/s^2), and t is the time (6 seconds). Plugging in the values, we get h = (1/2)(9.8 m/s^2)(6 s)^2 = 176.4 meters. Therefore, the height of the cliff is 176.4 meters.